The invention discloses a process for freezing and denitrating
sodium chlorate mother liquor by the aid of membrane methods. The process includes steps of (1), diluting the
sodium chlorate mother liquor, to be more specific, adding the
sodium chlorate mother liquor into water and diluting the
sodium chlorate mother liquor to allow the concentration of
sodium chlorate in the
sodium chlorate motherliquor to be lower than 200 g / L so as to obtain sodium chlorate
diluent; (2), carrying out pretreatment including rough
filtration, pH (potential of
hydrogen) value regulation, dechlorination and finefiltration on the sodium chlorate
diluent to obtain sodium chlorate pretreated liquor; (3), carrying out concentration, to be more specific, feeding the sodium chlorate pretreated liquor into a nano-
filtration membrane concentration
system by the aid of booster pumps and acquiring permeated liquor and concentrated liquor; (4), carrying out freezing and denitrating, to be more specific, feeding the concentrated liquor into a freezing
system, crystallizing the concentrated liquid, and carrying out
solid and liquid separation by the aid of a centrifugal
machine to obtain
mirabilite and
crystallization mother liquor; (5), carrying out recycling by means of mixing the
crystallization mother liquor and the sodium chlorate mother liquor with each other. The process for freezing and denitrating the sodium chlorate mother liquor by the aid of the membrane methods has the advantages that the process is simple, is low in cost and has a high additional value, new chemical impurities can be prevented from being introduced into the sodium chlorate mother liquor, and impurities in the sodium chlorate mother liquor can be effectively removed by the aid of the process.